This isn't the first digital restoration for "Sunset Boulevard," which earned 11 Oscar nominations and won three Academy Awards. "Sunset Boulevard" was restored a decade ago for its DVD release. "It was the first time that an entire film was scanned for restoration," noted Andrea Kalas, vice president of archives at Paramount Pictures.

But in the last 10 years, she said, digital technology has improved immensely. "Because it was Paramount's 100th anniversary, we knew we could do something really spectacular, using the tools that exist now to get that fantastic film noir look of the film."

One of the biggest hurdles was finding the best surviving elements for the restoration because the original negative of "Sunset Boulevard" no longer exists. Kalas said there is no record of what happened to the negative. ("Sunset Boulevard" isn't the only classic film with a missing negative; "Citizen Kane" and "Stagecoach" are among the seminal films whose original elements have suffered the same fate.)

Kalas and her staff found a duplicate negative that had been made from the original in the 1960s in the Paramount archive to use for the restoration. But the duplicate negative was not without its flaws.

"There were a few frames missing," Kalas said. "There was lots of cleaning and a few small tears."

Kalas worked with Technicolor on the restoration. "They have a lot of different tools at their hands ranging from standard restoration tools that are able to clean up [problems] to special effects tools when they need to do something particularly special. The capacity to restore it to its original glory is much more possible now than it had been before."

A 35mm print of "Sunset Boulevard" from the Library of Congress that was made from the original negative at the time of release was helpful in the restoration. That print was "our main reference for the film" to restore the correct shadings and shadows to John F. Seitz's atmospheric black-and-white noir cinematography.

"There's one scene where Holden is in the garage with Erich Von Stroheim and all you see practically is von Stroheim's face," said Kalas. "Everything else is in the darkness. We wanted to make sure we got that right."

The decades haven't dimmed the brilliance of "Sunset Boulevard." The film was a comeback for Swanson, who began her career in 1914. She gives an iconic performance as faded silent screen star Norma Desmond, who hires a struggling young writer (Holden) to help work on her comeback vehicle.

"It's a wonderful capsule of Hollywood," said Kalas. "The script is perfectly pitched. It doesn't hold back on its criticism [of Hollywood], but there's definitely a lot of affection."

Olson, who earned a supporting actress Oscar nomination as Holden's girlfriend, recalled that even during production, Paramount was abuzz that "Sunset Boulevard" was something special.

"Every day at 6 p.m., studio executives, directors and technical people attended the dailies," she noted. "There could be at least 15 movies being filmed at the same time. People would show up to see how the prior day's footage looked [of their film] and then leave immediately."

But a quarter of the way during production on "Sunset Boulevard," Olson said, "everyone stayed to watch the dailies. They had to bring in extra seats. They wanted to know what was going to happen next."